How do I resolve "Default Tax Code has not been set" message importing sales orders?

Before you import in sales orders either from a flat file or from a webstore import, you may need to set the default tax codes for both your customers and your inventory.  This can be quickly accomplished within Acctivate by browsing to File -> Configuration Management.  Once Configuration Manager opens, expand Customers -> Customer Options.  Here, you should set the Customer Default Tax Code.

Next, while still in Configuration Manager, expand Inventory -> Inventory Options.  Here, you can set the Taxable and Non-taxable Tax Codes.